Lightheartedness means cheerful, carefree ect.
This means the line "The sounds of water splashing and laughter echoed in the distance; Tim's friend's had gone for a late-night swim." is the phrase that is the correct answer, since it talks about the happy actions of Tim's friends.
Answer C.
I'm not sure since I can't read the passage, but I think D is least important.
The answer is: B. The doctor's payment for time spent with the lady
"The Dean's Provocation..." is a poem written by Lady Mary Wortley Montagu is a satiric poem written in response to “The Lady's Dressing Room” by Jonathan Swift both author are making fun of the gender interactions however on Montagu’s poem the doctor is a rich man that wants to pend time with a beautiful lady and ends up paying for it.
Animals usually play the antagonist in mythology. They are beasts that need to be defeated by the hero.